The Free On-line Dictionary of Computing (30 December 2018):

Large Installation Systems Administration

   (LISA) The USENIX systems administration conference.  It is
   now more general that its title suggests.  It is sponsored and
   organised by SAGE, the USENIX Systems Administrators Guild.

   (ftp://ftp.sage.usenix.org/pub/sage/).

   (1996-01-02)